66 273 Cam and Intake Thoughts

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oldmoparsrule

oldmoparsrule

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Hello,
I have the original 273 in my 1966 Dart. It is a 2 bbl car. The original heads were recently (13k miles ago) cleaned up and had hardened valve seats so it would run unleaded gas (as I was told by the original owner). The engine has 85k original miles on it, and runs well. I am looking for cam/ intake carb build up ideas.

I have a set of Spitfire headers that I am thinking about running with a true 2.5" dual exhaust. I do have a 4bbl (thermoquad) and a factory 4bbl intake off of a 1974 360. I also have access to an Edelbrock Carb (650 cfm).

My goal is to give the car more power, and an aggressive sound. It will not be a racer, but I do want to have some fun with it. I will keep all of the factory parts so I can replace them if the need arises.

So, should I run the 74 factory intake and carb?
Should I buy an aftermarket intake and run the Edelbrock?
What Cam should I run with the aforementioned set up?

And the magical question...any ideas on how much hp this set up with make?

I really appreciate your insight and wisdom. This is a great community!!!

Thanks,
Clint
San Gabriel (Los Angeles, CA)

1966 Dodge Dart 270 V8
1964 Dodge Dart GT /6 - Soon to have 360/727
 
Its real tuff to make a lot of horsepower on a low comp motor. I had a 67 273 that I angle milled the heads on to raise the comp. ratio. I also had a hughes cam he0914al grind that worked very well. It has 470I\458E lift and 209\214 at .050. It had a stock idle and good vacuum. You dont want a cam with lots of lope on a small low comp. motor. I sold my 273 short block and am parting out the rest of the valve train. I still have the cam lifters and rocker arms if you are interested.
 
Clint, if the heads you have now are the original 273 castings, you don't want to use the TQ manifold from the '74 360. The ports are much larger than the smaller 273/318 heads and will create a very bad reverse step that will cause turbulance (resistance to flow) in the port runner. Best to use one of the aftermarket aluminum manifolds for that application. Or a 273 4 barrell casting, but I believe they were square flange manifolds (AFB) and not spread bores. Others can help you more on that one. Good luck, Terry.
 
I'm with Terry. An aftermarket intake to look at would be the Edelbrock Performer. It has the small runners for the 273/318. So in that, the match will be good. That intake is also equiped to use the T-Q. So you'll save on getting a new carb there.

On the exhaust, the tube size is HP dependent. 2-1/4 for your engine (IMO) for about 1 hp per cube. If you plan to exceed that, 2-1/2 is fine. Large, but fine for the top end.

A cam is a little tuff to call with the surplied info. Tell us here the;
1. rear gear ratio. There should be a tag on the rear end cover with some numbers. Otherwise, the 1 of the other 2 ways to know is to do what probably hasn't been done to the car since new. Change your rear gear fulid and look at the ring gear for the ratio stamped on it. I'm not a fan of the other, pick up the rear and spin the tire and count the tire vs driveshaft revolutions for a approx. guess.

2. tire size. (Or what you intend to run)
3. are you gonna change the stall converter? and is it stock?
4. the cars weight. (The reggie has the cars close enuff approx. weight.)

Answer these questions and we'll be able to better zero in on a cam that will be better suited for your intentions.
 
If these are '66 heads don't they have the angled bolt pattern? The "D" dart manifold or equivalent would probably get it going. Cam is also a solid on that one isn't it? Racer Brown or Hughes would be good sources for parts for that one.
 
Great topic! This is exactly the dilemna I have with my 66 dart. I was looking to use an Edy performer intake, and a 500 cfm carb, because I figured that anything bigger would be too large. I was looking at putting in a purple cam for just a bit of lump in the exhaust note, but I'm not worried about a ton of HP. I figured if I change out the rear end, then I've got to worry about my tranny being the weak link. How far off am I in my thinking?

DaveZee
 
I really appreciate all of your thoughts and input. The 66 is my all original survivor car. I am building a stroked 360 for my 64...but that one is a year or two away from being a runner again...so I look at my 66 and have these nasty ideas of making it have a nice rumble and a little more power for cruising while the other one is being built. I know I really should not mess with a survivor car...but it is so tempting.

headsbikesmopars - I will have to keep my eyes open for a 273 4bbl manifold. I saw a few of them at the Spring Fling this year in LA...but did not buy anything. I will keep my eyes open.

BobsCuda67 - Thanks for your help. I will look into the Hughes cam. That sounds like what I would be looking for. I will add your post to my "wish List" for the 66.

Rumblefish - Thank you very much for your input. My car weight around 2800 lbs. It has the factory 14" steel wheels, with the factory converter. I am not sure of the gear ratio, but I would imagine it to be highway gears. I will take your advice on the tube size for the exhaust. The tendency is to put a large diameter tube...but I know it can kill bottom end torque. A buddy of mine had a Skylark that ran 3/10 faster in the quarter WITH his exhaust than with open headers...

Dartjack - Yes, it is a solid lifter motor. I am told that my 66 heads should not be of the angled bolt variety, but I am not positive. Thanks for the additinal nod towards the Hughes cam.

DaveZee - I will have to keep an eye out for you around LA. Do you ever go to the Bobs Big Boy in Burbank on Friday nights? We may have to plan a trip there to compare notes. I will bring the 66 with me.

Thanks,
Clint
San Gabriel (Los Angeles)
 
273 1966 heads have the "normal" bolt pattern,
double check the casting numbers, under the cylinder head {valve} covers.

I suggest either a stock type 273 4 bbl intake,
or an old LD4B, for use on a 273 or low compression 318.
I have a rare "Marine" 273 4 bbl intake, there are a few around.
The Marine ones you can use a 600 Edelbrock on without an adapter.

The smaller runner size will work better than the 340 sized
runners on the newer intakes.

If you want you can convert to hydraulic cam,
what rear gears are you using/ plan to use?

I am using 2.25" dual exhaust.
My engine is stock bore, low compression 318.(1973 donor)
 
Clint-

I live in Burbank, and I try to get out to Bob's with the family every few weeks. My plan is definitely to go on my B-day, September 8th, and drive the Dart there for the first time. She's still in kinda rough shape, but I figure it's the best way to get info.

Are you coming out for Fall Fling in October?

Dave
 
An Edelbrock Performer 318/360 intake would be a good intake for this application.
It has the intake ports cast for the 273/318 ports, but larger runners behind these port openings.
This intake also allows you to run any of a number of carbs, small square bore AFBs, large square bore Holley, AVS, or Carter-Brock and Spreadbores like TQs and Quadrajets.
It will accept either the RV-2 A/C pump or the '79-'92 Rotary A/C pump.

On top of that, they are a dual plane, which is a good, street friendly design.

Another cool thing about them is that they are usually pretty cheap, in fact I know of one in nice shape for $75 and they go even cheaper, sometimes.

I suggest something like a stock 340 cam, as that 2 barrel 273 is really down on compression.

Mark.
 
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